Although the beneficial effects of Yoga for increasing psychological well-being and decreasing stress and reducing cardiovascular risks have been reported, no studies to date have examined intervention Yoga training to investigate its effects on bone metabolism and hormone responses. PURPOSE: The purpose of this study was to examine the effects of an 8 month Yoga exercise program on bone biomarkers, areal bone mineral density (aBMD) for the total body, dual proximal femur, and lumbar spine and volumetric bone mineral density (vBMD) for the tibia and forearm in premenopausal women. A secondary purpose was to examine IGF-I, body composition, and muscular strength changes. METHODS: Thirty-four healthy women were randomly assigned either to a Yoga group (YE, n=16, mean age; mean±SD, 45.73±3.82) or a control group (CON, n=18, 43.22±4.16). Subjects in YE group performed 60 minutes of an Ashtanga Yoga series two times per week with one day between sessions for 8 months in morning sessions (6:30 - 7:30 am, Mondays/Wednesdays). Each Yoga session consisted of 15 minutes of warm-up exercises, 35 minutes of Ashtanga Yoga postures and 10 minutes of cool-down with relaxation. Session intensity was progressively increased during the 8 months. Subjects in CON group did not receive the Yoga exercise intervention, and they were encouraged to maintain their normal daily lifestyle monitored by the bone-specific physical activity questionnaire at 2 month intervals for 8 months. Bone formation (bone alkaline phosphatase, Bone ALP) and bone resorption (tartrate-resistant acid phosphatase, TRAP5b) were assessed at baseline and after Yoga intervention. aBMD and vBMD were measured using DXA and pQCT, respectively. Body composition (DXA) and muscle strength (1RM) for leg press (LP), knee extension (KE), knee flexion (KF), lat pull down (LPD), shoulder press (SP), and biceps curl (BC) were measured. RESULTS: There were no significant differences between the groups in age, height, and weight at baseline. A significant group õ time interaction was detected in serum Bone ALP (p0.05) in percent changes for TRAP5b and ratio of Bone ALP to TRAP5b, but there was a trend (p=0.061) for serum TRAP5b, which increased slightly in YE group whereas it decreased in CON group (1.0±4.6% vs. -8.3±6.5%). No significant BMD differences and percent changes were detected in the total body, lumbar spine, and dual femur sites between groups (p>0.05). However, a group õ time interaction was detected (p0.05). However, a significant time effect was detected (p0.05). No significant differences and percent changes in weight, total fat mass, and %fat were detected (p>0.05). However, bone free lean body mass in both groups significantly increased (p0.05). Also, two-way mixed factorial ANOVA with repeated measures detected a significant time effect (p0.05) after the 8 months. CONCLUSION: The findings of this study suggest that the 8 month Ashtanga Yoga was able to generate sufficient mechanical loading forces to elicit increases in bone formation (Bone ALP) as well as increases in leg press muscle strength in premenopausal women
